The long term objective is to better understand the dynamic process of mammalian fertilization. The development of many tools in molecular biology and the emerging technologies for in vitro maintenance of sperm cells, oocytes and finally fertilization in vitro enhances the opportunity to isolate and identify critical morphological, biochemical and physiological changes vital to the formation and development of a normal conceptus. Specifically, the objectives of this research are: (1) to characterize changes in lipid composition of sperm call membranes associated with capacitation and the acrosome reaction; (2) to improve existing systems of in vitro fertilization; (3) to record on video tape and analyze through computer-enhanced image analysis the dynamic events surrounding in vitro fertilization; and finally (4) to extend this knowledge and technology to the study of early post-fertilization development. Much of the previous research in this area has involved a series of isolated observations. By combining the techniques of biochemical and ultrastructural analysis at various stages in well-controlled systems, and continuously recording changes associated with fertilization this research should be helpful in interpreting and integrating the dynamic events associated with fertilization. The development of these techniques will (1) facilitate the opportunity to detect when and how various environmental conditions impinge on early development and (2) directly improve the process of in vitro fertilization in humans and in animals.